An electrophotographic type image forming apparatus forms an electrostatic latent image on a photoconductor by optical writing, and develops the electrostatic latent image to obtain a toner image. When the toner image is transferred onto a sheet and fixed onto the sheet with heat or pressure, an image is formed on the sheet.
Known is a technique in which, in a full-color image forming apparatus, a toner image is transferred onto an intermediate transfer body, and the transferred toner image is transferred onto the sheet from the intermediate transfer body. For example, a color toner image is temporarily transferred (primary transfer) onto the intermediate transfer body such as an intermediate transfer belt and an intermediate transfer drum. After color toner images of a plurality of colors are superimposed on the intermediate transfer body, the color toner images are transferred (secondary transfer) onto the sheet from the intermediate transfer body. Thereafter, the color toner images are fixed onto the sheet, and a full-color image is obtained.